Siege of Petersburg

The Siege of Petersburg was a nine-month siege of the Confederate-held city of Petersburg, Virginia by Ulysses S. Grant's 125,000-strong Union army during the final months of the American Civil War. After several unsuccessful assaults on the city, the Union forces built trenches and besieged the city, which fell on 2 April 1865.

Final offensive plans
In March 1864, Major-General Ulysses S. Grant was given command of the Union Army by President Abraham Lincoln and decided to pursue an aggressive strategy against the crumbling Confederacy. Grant planned to join forces with George Meade to attack at Robert E. Lee's Confederate Army of Northern Virginia from the north as Benjamin Butler would drive on the Confederate capital of Richmond from the southeast, Franz Sigel would secure the Shenandoah Valley, William T. Sherman would invade Georgia, George Crook and William W. Averell would operate against railroad supply lines in West Virginia, and Nathaniel P. Banks would capture Mobile, Alabama. However, Butler's army was bogged down in the Bermuda Hundred Campaign, Sigel was soundly defeated at the Battle of New Market in May 1864 and replaced by David Hunter, and Banks was distracted by the unsuccessful Red River Campaign, but Crook and Averell cut off the last railroad linking Virginia with Tennessee and Sherman's Atlanta Campaign was successful, although it dragged on due to John Bell Hood's fierce resistance.

Overland Campaign
On 4 May 1864, Grant and Meade's army crossed the Rapidan River and entered the Wilderness area of Spotsylvania County. Grant's army suffered heavy losses against Lee's army at the Battle of the Wilderness (5-7 May) and the Battle of Spotsylvania Court House (8-21 May), but he outflanked Lee to the southeast both times, keeping Lee on the defensive as he retreated towards Richmond. Grant's attacks were repulsed with heavy losses at the Battle of Cold Harbor from 31 May to 2 June, and, while Grant regretted the battle and his heavy losses, he relied upon a steady flow of reinforcements, while the Confederates could not replace their losses due to their smaller population. The Overland Campaign cost Grant 41% of his army, which was easily replaced, but Lee lost an irreplaceable 46% of his men.

Siege
On 12 June 1864, Grant and his army crossed the James River and bypassed Richmond, instead intending to isolate Richmond by seizing the railroad junction of Petersburg to the south, the main supply base and depot for the entire region. Lee initially feared that he would be besieged in Richmond, so P.G.T. Beauregard initially held Petersburg with a very small force. Grant and Meade's Army of the Potomac and Butler's Army of the James faced Lee's Army of Northern Virginia and Beauregard's 10,000 troops defending Richmond. At Petersburg, 15,000 Union troops faced just 5,400 men under Beauregard.

First and Second Battles of Petersburg
Although Butler's initial assault on Petersburg on 9 June 1864 had failed with 40 Union and 80 Confederate losses, Grant had Butler lead a second assault on the city from 15 to 18 June 1864. Henry S. Wise held the city with just 2,200 troops, facing 16,000 Union soldiers from the XVIII Corps under William Farrar Smith and August Kautz. By the night of 15 June, the city was in Union hands, but Beauregard withdrew Robert Hoke and Bushrod Johnson's forces from the Howlett Line at Bermunda Hundred to join the new Petersburg defensive line. Beauregard now had 14,000 men to face 50,000 Union troops, and the Union launched uncoordinated attacks against the Confederate lines on 17 June. On 18 June, Lee sent two divisions to reinforce Beauregard's forces, and 20,000 Confederates now faced 67,000 Federals. The entire Union army failed to punch through the lines in one attack, and, when Lee assumed personal command of the Petersburg defenses, the Union launched a disastrous attack which mauled Orlando B. Wilcox's division and left Colonel Joshua L. Chamberlain wounded. The 1st Maine Heavy Artillery Regiment lost 632 of 900 men in the assault, the worst losses suffered by any regiment in a single battle during the war. Meade decided to order his army to dig in, having suffered 11,386 losses; the Confederates lost 4,000 men.

Cutting the railroads
On 21 June 1864, Grant decided to secure the three remaining open rail lines connecting Richmond and Petersburg: the Richmand and Petersburg Railroad, the South Side Railroad, and the Weldon Railroad. On 22 June, II Corps and VI Corps were sent to probe the Weldon Railroad, but VI Corps entrenched after coming under attack from Cadmus Wilcox's Confederate division. The Confederate general William Mahone hid his attack column in a ravine and ambushed Francis C. Barlow's division, which quickly collapsed. John Gibbon's division was also ambushed and forced to flee for safety. Darkness ended the fighting, which resumed on 23 June. II Corps retook the lost ground and the earthworks as the Confederates retreated, and Lewis A. Grant's Vermont soldiers began to tear up the railroad tracks. However, another Confederate ambush took many prisoners and drove the Vermonters back. The Battle of Jerusalem Plank Road cost the Union 2,962 men, while the Confederates lost 572.

Concurrently, James H. Wilson and August Kautz launched a raid to destroy as much track as possible south and southwest of Petersburg. They inflicted minor damage on the railroads before being forced back at the Battle of Staunton River Bridge on 25 June, leaving the Staunton River bridge intact. As they withdrew east, their path was blocked by Wade Hampton III's cavalry, and they failed to break through the Confederate lines in the Battle of Sappony Church on 28 June 1864. They escaped under cover of darkness, and, after the First Battle of Reams Station on 29 June, they found themselves caught in a trap without immediate aid. They were forced to burn their wagons and spike their artillery, as well as abandoning 300 escaped slaves. The federals destroyed 60 miles of track, which took the Confederates several weeks to repair, but lost 1,445 men in the process in a disastrous expedition.

First Deep Bottom and the Crater
Grant then planned a two-pronged assault on Petersburg, so he had Winfield Scott Hancock's II Corps and two division of Philip Sheridan's cavalry corps launch a faint attack across the river to Deep Bottom to threaten Richmond. Lee ordered that the Richmond lines be reinforced to 16,500 men, and Joseph B. Kershaw's took up positions on the eastern face of New Market Heights while Richard H. Anderson - reinforced by Henry Heth and William Henry Fitzhugh Lee - were sent to Deep Bottom. The First Battle of Deep Bottom was a successful distraction of Lee's forces, ending on 28 July.

Two days later, on 30 July, Grant launched his main assault on Petersburg by using Henry Pleasants' plan to  blow a hole underneath a fort at Elliott's Salient along the Confederate I Corps' lines. At 4:44 AM, charges hidden in a long mine shaft underneath the Confederate line exploded, instantly killing up to 350 Confederate soldiers. However, James H. Ledlie's Union 1st Division foolishly charged into the crater instead of around it, as they did not know that they would not be provided with ladders to climb out. William Mahone's Confederate troops counterattacked and massacred Ledlie's soldiers; Ambrose Burnside, in command of the assault, decided to send in Edward Ferrero's African-American division to continue the battle rather than retreat. They also went down into the Crater, continuing the massacre, and the Union lost 3,798 men to the Confederates' 1,500; Burnside was relieved of command.

Second Deep Bottom
Also on 30 July 1864, the Confederate general Jubal Early burned down the northern town of Chambersburg, Pennsylvania, and Lee sent Kershaw's division from Anderson's corps to reinforce Early. Misinterpreting this movement as the redeployment of the entire Confederate corps, Grant decided to intercept the corps and destroy it. On 14 August, David B. Birney's X Corps attacked the Confederates at Deep Bottom. The battle has the same effect as the first one, with Lee sending W.H.F. Lee and Wade Hampton's divisions north to protect Richmond. On 16 August, David McMurtrie Gregg's Union cavalry met Lee's cavalry division on the Charles City Road, and, in the ensuing battle, CSA Brigadier-General John R. Chambliss was killed. The Union attacks ultimately failed, and Hancock withdrew his force back over the James on 20 August; the Union lost 2,900 men, while the CSA lost 1,500.

Globe Tavern and Second Reams Station
While the Second Battle of Deep Bottom was raging, Grant sent Gouverneur K. Warren's V Corps to launch another attack against the Weldon. On 18 August 1864, he reached the railroad at Globe Tavern, where he had Brigadier-General Charles Griffin destroy the track as Brigadier-General Romeyn B. Ayres' division block any Confederate advance from the north. At 1:00 PM, the Confederates met Ayres' force, so Warren sent Samuel W. Crawford's division to outflank the Confederates. A.P. Hill sent three brigades to meet the Union advance, and the Union forces were forced back towards the tavern by nightfall. John G. Parke's Union IX Corps arrived that night, while W.H.F. Lee's Confederate cavalry division reinforced the CSA. The Confederates launched a failed attack on 19 August, and further attacks failed on 21 August. The Union lost 4,296 men, while the CSA lost 1,620. However, the Confederates lost a key section of the Weldon Railroad and were forced to use wagons to carry supplies, a minor inconvenience. The Battle of Globe Tavern was the first Union victory of the campaign.

However, Grant wanted the Weldon closed permanently, so he sent Hancock's II Corps south from Deep Bottom. Nelson A. Miles and John Gibbon's division occupied Reams Station and destroyed further stretches of railroad tracks. Fearing that the Union could cut off his retreat route via Dinwiddie Court House, Lee sent Hill and 10,000 men to attack II Corps in the Second Battle of Reams Station on 25 August. The Confederates outflanked the Union and forced them to retreat, inflicting 2,747 Union losses while suffering 814 losses. They again lost a key portion of the Weldon Railroad, leaving only the South Side Railroad available to supply Lee's army. On 15 September, Hampton led the daring Beefsteak Raid, stealing 2,486 cattle from the Union and fending off Union attempts to recapture their food.

September offensives
On 28-29 September, Butler's Army of the James crossed the James River to assault the Richmond defenses north of the river in the Battle of Chaffin's Farm, which resulted in stalemate as both sides entrenched. However, Lee was forced to weaken his lines at Petersburg by sending reinforcements to defend Richmond. Grant also had two divisions of IX Corps cut the Confederate lines of communication southwest of Petersburg in the Battle of Peebles Farm, also resulting in stalemate, but extending the Union left flank.